Fixture design

[sasha1]

I need to design a heat treatment fixture, my problem being that I need to work out size achieved at a tempreture of 700deg C for Stainless 316. I can only get the coefficient of expansion for this material up to 500deg. From that data it would appear to be 0.0000195

I know its not a Ug question but any advise would be much appreciated.
Dennis

 

[hudson888]

You can probably graph the rate of expansion up to 500deg and extrapolate, but if graphs are stopping there better to ask the suppliers of your material or even comparable alternate materials why it is that they do so. From what I remember of the metallurgy classes I took a very long time ago it seems possible that extreme heat treatment may change the properties of stainless steel at higher temperatures so that it fails to return to an equivalent state when cooled.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

 

[DesignJunkie]

Dennis!

What a coincidence, I'm also designing a heat treat fixture (but not using 316 ss).

http://www.matweb.com

tells me that the CTE of 316 austenitic SS is non-linear, which is to say that it increases as you get to higher temps. Not sure if this is an issue for you or not.

http://www.matweb.com/search/DataSheet.aspx?MatGUID=5edc39d3b0fd44efa9fdd90d049c3737

Here's a data sheet that goes up to 871C (1600F). As you can see, there's some change but not a ton between the two CTE's listed. If your fixture is larger then of course you can expect more growth. Hope this helps.

-DJ